This is a request for an ADAHMA RSDA focusing on hemispheric specialization and interaction at the interface of language and cognition. A convergent research program is outlined which studies neurological patients and normal subjects and combines behavioral, anatomical and physiological methods. Technological developments include a powerful computer-based laboratory for laterality research and a eye-tracker with scotoma simulator for hemispheric occular scanning without attachments to the eye. Theoretical work will continue on behavioral models of laterality effects and conditions for parallel independent information processing in the two hemispheres. One set of experiments will study independent lexical access and organization, syntactic and pragmatic competence and associated cognitive abilities in each of the two hemispheres. A second set of experiments will analyze individual differences in regional patterns of callosal connectivity using behavioral, anatomical and physiological measures, in relation to cognitive profile, handedness and gender. Biological and environmental conditions that change hemispheric function and callosal connectivity will be investigated. A third set of experiments investigates issues of monitoring and control in interhemispheric relations, including learning, metacognition and error correction. Results promise better understanding and possible control of cognitive pathology due to abnormal cerebral activation or faulty interhemispheric communication. The data will contribute to theoretical cognitive neuroscience by understanding how language is organized in the brain and how independent, parallel cortical processing modules interact. Plans for professional growth include (1) Collaborative research with other psychologists, linguists, and neuroscientists, (2) intensive study of neuroanatomy, neurophysiology and statistical analysis, and (3) tutorial visits to other labs to study techniques of event-related potentials, magnetic resonance imaging, clinical neurology, and cognitive psychology.